Plastic compositions and process for producing the same



Patented July 15, I952 UNITED STATES 2,603,616 ICE PLASTIC COMPOSITIONS AND PROCESS FOR PRODUCING THE SAME Lawrence W. Newton, South Charleston, W. Va., assignor to Union'Carbide and Carbon Corporation, a corporation of New York No Drawing. Original application January 28,

1948, Serial No. 4,952. Divided and this application April 25, 1951, Serial No. 222,932

19 Claims. (Cl. 260-303) This invention relates to the production of a new class of esters of thiopolycarboxylic acids; and more especially it concerns the production of polyesters of thiotetracarboxylic acids .and thiohexacarboxylic acids, many of which have utility as plasticizers for vinyl resins and for other synthetic resinous plastic materials such as cellulose acetate and other cellulose esters of the lower fatty acids. The invention also relates to a new class of thiopolycarboxylic acids which can be formed by the hydrolysis of the corresponding esters. The invention also relates to plastic compositions comprising vinyl resins, and those comprising resinous cellulose esters of lower aliphatic acids having two to four carbon atoms, such as cellulose acetate and cellulose propionate, which compositions contain one or more of certain of these esters of thiopolycarboxylic acids functioning therein as plasticizers or modifying agents for the resins. The esters of the invention are effectiv plasticizers for vinyl resins made by polymerizing at least one vinyl compound including a vinyl halide, and especially such resins which contain 85% or more of the halide in the polymer, such as the polyvinyl chlorides and the vinyl chloride-vinyl acetate copolymers containing 85% or more of the chloride in th polymer.

Esters of the new class are produced, in accordance with the invention, by reacting a diester of an alpha, beta-unsaturated dicarboxylic acid, and especially those having conjugated double bonds, or a corresponding triester of an alpha, beta-unsaturated olefinic tricarboxylic acid, with hydrogen sulfide at a temperature within the range between C. and 300 C. When employing a basic condensation catalyst in the process it is preferred to conduct the reaction at temperatures between 0 C. and 100 C. In the case of an uncatalyzed reaction, higher temperatures within the range from around 150 C. to 300 C. preferably are used with pressures above atmospheric. The polyesters of the resultant saturated thiopolycarboxylic acid are recovered from the resultant reaction mixture, preferably by fractional distillation under high vacuum.

The new compounds are saturated aliphatic monothiodipolycarboxylic acids having at least eight carbon atoms, and containing only carbon, hydrogen, oxygen and sulfur in the molecule, and the tetra-and hexaesters of such acids wherein the hydrogen atom of each carboxyl group is replaced by a radical selected from the class consisting of the alkyl, aralkyl, alkoxyalkyl, aryloxyalkyl, cycloalkyl, halogenated alkyl, alkoxyalkoxyalkyl, aryloxyalkoxyalkyl and alkylene radicals.

The preferred esters of the new class of compounds have structures apparently corresponding to the formula:

HCRZOOORB CRCOOR4 CRCOOR HCR OOOR wherein R may be either-hydrogen, a lower alkyl group or a -CI-I(al1-;yl)C( )OR group; B. may be either hydrogen, alkyl a CII2COOR group or a CH(alkyl) C003 group; R being hydrogen or alkyl when R. is either .CHzCOOR or -CH(alkyl)COOR and R being hydrogen or alkyl when R is --CH(alkyl)COOR and R R R and R are the same or different alkyl, aralkyl, cycloalkyl, alkoxyalkyl, aryloxyalkyl, halogenated alkyl, alkoxyalkoxyalkyl, aryloxyalkoxyalkyl, or alkylene groups.

The reaction with hydrogen sulfide may be conducted in the presence of a solvent for the reactants which is inert to the latter. The use of such a solvent is desirable when the ester of the olefinic polycarboxylic acid is a solid under the reaction conditions, or when such ester is a poor solvent for hydrogen sulfide, or for the catalyst, when employed. Suitable solvents found useful are aliphatic alcohols, such as ethanol and butanol; ethers, such as diethyl ether, the monoand dialkyl ethers of the glycols and polyglycols, and dioxane; and aromatic hydrocarbons such as benzene.

Although the reaction will proceed slowly in the absence ofa catalyst, it is usually desirable to conduct the reaction in the presence of a catalyst in order to cause the reaction to proceed at a commercially practicable rate in simple apparatus at atmospheric pressure. The non-cata-' lytic reaction usually requires the use of high temperaturesv and superatmospheric pressure in pressure vessels. If desired, pressures above atmospheric may be used in the presence of a catalyst.

Catalysts suitable for use in the process are relatively strongly basic compounds. Those, such as ammonia, sodium hydroxide, etc.,which react with the ester of the olefinic polycarboxylic acid to form weak bases are not as effective as the preferred catalysts. The latter includethe strong organic bases, such as piperidine, the secondary and tertiary aliphatic amines such as diethylamine and triethylamine; and the quaternary ammonium bases such as trimethylbenzyl ammonium hydroxide. Weak organic bases such as pyridene are less effective as catalysts. Inorganic bases and inorganic-organic bases such as sodium hydride and sodium butylate are effective but are difiicultly removable from the reaction products. Ammonia and the primary amines such as butylamine show relatively poor catalyst activity,;probably due to reaction thereof with the ester starting material to form weak bases.

Neutralized bases such as ammonium carbonate do not function as catalysts.

The reactions involved in the production of the polyesters of the saturated thiopolycarboxylic' acids are represented by the following equations:

CRCOOR3 ncrucoon CRCOOR4 ris-on'ooom omoooR HORZCOORK noR oooR on 000m HSCR'COOR oR'c.ooR

[CRCOOR Hcmooom acid containing only a small amount of the mercapto compounds. p

In a preferredpractice of the invention; successive portions of hydrogen sulfide are diffused through a mixture ofthe, diester of the selected alpha, beta-unsaturated olefinic polycarboxylic.

acid and the catalyst while maintaining the re action temperature between C. and 100 C.

When no catalyst is used, temperatures as high as 150 C or higher conveniently can be used in conjunction with superatmospheric pressures, and the yields of the desired ester are relatively low. The ester and catalyst'may be dissolved in an inert volatile solvent when desired. The resultant reaction mixture then is fractionally distilled under vacuum to remove solvent and'other volatiles. The fraction containing the desired ester is distilled under high vacuum, usually-in a falling film type of molecular still, yielding a purified polyester of a saturated thiodi(polycarboxylic) acid. i V

Among the polyesters of alpha, beta-unsatu- EXAMPLE 1 Tetmltfzethyl thzodz'succinate During 4.5 hours hydrogen sulfide was diffused.-

through a mixture of 1,100 parts of dimethyl maleate and 33 parts of triethylamine ina glass.

reaction tube fitted with a glass diffuser. During this period 112 parts of hydrogen sulfide Were absorbed, and the reaction temperature was held at 70 C.80 C. The liquid reaction products were stripped of volatiles under vacuum and the residue was distilled in a falling film type rated olefinic diand tricarboxylic acids useful in the process may be mentioned thedialkyl, di-

aralkyl, dialkoxyalkyl, diaryloxyalkyl; dihalo- .genated alkyl, dialkoxyalkoxyalkyl, diaryloxyalkoxyalkyl, dicycloalkyl and dialkylene esters,

such as dimethyl, diethyl, di-isopropyl, dibutyl, di-n-hexyl, di-Z-ethylhexyl, di-5-ethylnonanyl-2, dicyclohexyl, dibenzyl, di-methoxyethyl, diphenoxyethyl, di-methoxyethoxyethyl, "diphenoxyethoxyethyl, di-beta chloroethyl, di-betabromoethyl, divinyl and diallyl esters of such j acids' a's'maleic and fumaric acids; methylene malonic' and ethylidene malonic acids; alkylmaleic acids, such as methylmaleic (citraconic) acidand ethylmaleic acid; itaconic acid; mesaconic'acid; and the corresponding triesters of alpha, beta-unsaturated olefinic tricarboxylic acids such as acomtic acid, and the alphaand gamma-alkyl aconitic acids. 7

' In the following examples which illustrate the invention, all parts recitedare in terms of weight unless otherwise indicated.

molecular still. The fraction distilling at 175 C. under a pressure of 0.5 millimeter of mercury was tetramethyl thiodisuccinate in the form of a viscous liquid having a refractive index at 20 C.

of"1.4779 and a specific gravity at 30C. of 1.255.

Upon standing several weeks the ester crystallized. Recrystallization. thereof yielded a white solid melting at 42C i I EXAMPLE? I Teimbutg/Z thz'odisaccinate .During' 4 hours '33 parts of hydrogen sulfide were absorbed in vaimixture of 417 parts of dibutyl maleate. and .5 parts of triethylamine contained in a glass reactor tube provided with a hydrogen sulfide difiuser while'm'aintaining the mixture at temperatures ranging between 4313. and 57 C. The reaction" products were stripped of volatiles in a vacuum still to a kettletemper ature of C5160 C'Junder 1 millimeterior" mercurypressure. The residue was distilled ina molecular type still. -'The.fraction distilling: at

g 156 C. under 0.05 millim'eterof mercury pres:-

sui'e was 'tetrabutyl thiodisucc'inate. other properties recited in TableI.

I EXAMPLE 3 Tetra-n-hezryl thzodisuccinate A stream of hydrogen sulfide was diiiusedduring twelve hours through a mixture of 970 parts of cli-n-hexyl maleate and 11 parts of trieth ylamine held at 40 C.-60 'C. During the reaction an extra 1 parts of triethylamine were added. The resultant reaction mixture was stripped of volatiles in a Claisen type still to a kettle'temperature of 256 C. at 3.6 millimeters of mercury pressure. A yield of 920 parts of crude: tetrahexyl thiodisuccinate was secured which, upon redistillation in'a molecular'type still, boiled at 183 C under 25 microns of mercury pressure, and had the'pther. :properties recited in Table I.

EXAMPLE 4 v I T etra (2 -ethyliz.exyl) thiodisuccinate During 5 hours 21 parts of hydrogen sulfide,

properties recited inTable I.

Tetra(beta-meth o-ryethyl) thz'odisucciv ate During 2' hours hydrogensulfide was diffused through a mixture of 464 partsof di(b eta methoxyethyl) maleate and 10.6 parts of v trieth ylamine in a glass reaction tube, 41pparts of-the hydrogen sulfide being absorbed. Thetemperature ranged between25 C. and 63C. The reaction mixturewas stripped in a pot stillto a kettle temperature of 145 C. at one millimeter of mercury pressure, yielding 466 parts of crudetetra- (methoxyethyl) thiodisuccinate. Upon fractionally distilling the'crude material ina molecular still; the purified ester was secured at a. viscous, partially water-soluble,- liquid, distilling at 220 C'. at'0.2 millimeter of -Iner'cur'y.pressure; and having the other properties recited in Table I, The'jester crystallized onv standing, and the recrystallized material melted. 'at 42 C. j

Tetra (beta-phenoxyethyl) thiodisuccinate During 11.5 hours hydrogen sulfide was diffused througha mixture of 362 parts of di(beta-' phenoxyethyl) maleate, 400 parts ofben'zene; and

3.8 parts of triethyla'inine within a glass reaction tube maintained 5 at 50 C.-'75 C. The" reaction mixture Was stripped of volatiles by distillation to a kettle temperature or. 150C. at 5 millimeters 2of.., mercury pressure, yielding 3'77- parts of crude tetra(beta-phenoxyethyl) thiodis'ucci nate in the form of a' liquid-too viscous at room temperature to pour. Thematerial eventually crystallized to a White solid which, after recrystallization, melted at 65 C.-6'7 C.

EXAMPLE '7 T etra(2-ethylbutyl) thiodisuccinate During 4 hours hydrogen sulfide was diffused I through a mixture of 606 parts of di(2-ethylbutyDmaleate and 6 parts of piperidine in a glass reaction tube maintained.v at 51 C.-66 0., 40 parts of hydrogen sulfide being absorbed. The crude reaction mixture was strippedby distillation to a kettle temperature of 147 C. at a pressure of 0.5 millimeter of mercury; and the residue was distilled in a molecular type still, yielding purified tetra(2-ethylbutyl) thiodisuccinate in the form of a light yellow liquid having the proper-'- ties recited irfTableI;

"-5- Hexaethylthiodfltricmrballylate) Hydrogen sulfide was passed through a glass reaction tube fitted with a glass diffuser and containing'750 parts of triethyl aconitate and 7.5 parts I of diethylamine, maintained between 27 'C. -59 C. During 4.5 hours operation 60 parts of hydrogen sulfide were reacted. The crude reaction mixture was distilled in a fallin film type molecular still, yielding a refined hexaethyl thiodi tricarballylate in the form of an oily liquid boiling. at.1'71 C. under 3. microns of mercurypressure, and having the otherpropen ties recitedinTable I v. r In-similar mannerhydrogen sulfide was dif fused through tributyl aconitate containing-1% diethylamine and about 25% of benzene during 3 hours at 32 C.- 51 C. The reaction mixture was-stripped inv a pot still to a temperature of C. at 2 millimeters of mercury pressure and the residue distilled in a molecular type still, yielding ,hexabutylthiodi(tricarballylate) as an oily liquid boiling at 183 C. at 5 microns of mercury pressure, and having the other properties recited in Table I. It was compatible with a 'vin lpfihloride-vinyl acetate copolymer resin to give a'clearflexible sheet containing 33% t -the compoundf, 1 EXAMPLEQ,

j Tetmbutyl thiodi(alplt -methylsuccmate) ilquringg'l55 hours'hydrogen sulfide was passed through 1 a. mixture of 600 parts of dibutyl itaconate and 6 parts of .triethylamine ina glass reaction tube maintained at 35 .C. An additional 6;parts of triethylamine and 6 parts of die'th ylamine were added during the reaction period; and 21 parts of hydrogen sulfide were absorbed. The crude reaction mixture was stripped of volatiles up to a kettle temperature of 150 C. at one millimeter of mercury pressure; and the residue therefrom was distilled in a falling film type molecular still to provide 1'71 parts of refined tetrabutyl thiodi(alpha-methylsuccinate) as a light yellow liquid boiling at 225 C. at 1.5 millimeters of mercury pressure, and having the other properties recited in Table I.

EXAMPLE 10 Tetrabenzyl thiodisuccinate Hydrogen sulfide was difiused through a mixture of 195 parts of dibenzyl maleate, 400 parts of benzene, and 5 parts of diethylamine. During the first 10 minutes the temperature rose from 25 C. to 50 C. and then subsided gradually during the remaining portion of the 1.5 hour reaction time. The reactor and its contents absorbed 29- parts of hydrogen sulfide'as judged by gain in weight. The benzene 'solvent Wasstrippedofi in a Claisen type still to a kettle temperature of 205 C. at 2.5 millimeters of mercury, yielding 204 parts of a yellow syrupy liquid which crystallized on standing. A portion of this product was recrystala lized from ethanol, yielding the white Waxy solid tetrabenzyl thiodisuccinate with -a freezing point of 492 C.-49.4 C. k

This 'material Was compatible with. a vinyl chlorideacetate copolymer resin at 33% concentration to give a clear but rather stiff sheet.

Table I M I R Compound g Boiling Point PC. fg 'c speelfigzgravlty 0C Tetra'methyl thiodisuceinate 42 1758f 0.5 mm. pressure.-. 1.4779 at 1.2553 at 30C. Tetraethyl thiodisuccinate. 222 at 5.5 mm. pressure... 1.4643 at 1 1491 at 20C Tetrabutyl thiodisuccinate- 156 at 0.05 min. pressure... 1.4589 at 1 0545 at 20C Ttrahex' lthiodisuccinste. 183 at 25 microns pressure. 1.4596 at 1.0083 at 20C Tetra(2-ethylhexy1) thiodisuccinate 4 183 at 17 microns pressure. 1.4610 at 0.9821 at 20C Tetra(beta-methoxyethyl) thiodisuccinate.. 220 at 0.2 mm. pressure..- Tetraisopropyl thiodisuccinate at 1.5 mm. pressure. 1.4538 at 1.072 at 20C Tetra(2-ethylbutyl) thiodisuccinate 231 at 0.5 mm. pressure... 1.4654 at 1.016 at 20C Hexaethyl thioditricarballylate 171 at 3 m crons press re.. 1.4681 at 1.160 at 30C Tetra(2,6- iimethyl-heptyli)tliio'disuccinate 156 at 2 microns pressure-. 1.4527 at 0.942 at 20C. Tetrabutyl thiodi-(alpha-methyl-succinate). 225 at 1.5 mm. pressurem- 1.4644 at 1.046 at 20C. 183 at 5 microns pressure-. 1 at 1.0622 at 20C Hexabutyl thiodi-(triearballylate) I V amt-valuable plasticizers" ifo a eoaeic 7 The :tetralalkyl esters or thiodisuccinici acid 'inyl resins; and especially for those resinoufs ol'y rners} and copolymers made from-at least- {'one monomeric 7 on a two-roll mill; and-Was examined to evaluate the last-namedeem unu -as plasticizera 'Ifhe resin was a copolymer; of vinyl chloride" and vinyl I resins:

acid also are compatible with copolymers of vinyl chloride and vinyl acetate in up to at least 33% as tetramethyl, tetraethyl and tetra (methoxyethvinyl?ompound' including-i{a kiinyl halideafid acetate containi g dfl 1i 'ti chloride infithie containingat (least 85% of the' halidei -t polymer." compo ition had a tn'silestr'ength polymer. Al'nb l h isiiwarelthe Polyvinyl 0 131 0 pounds persu iare"iiichfanult ifiat 51 ch1orides; co bIymerS :of ivinyichloride" with g fib 5z5o% m er a etreee eriaqoq' pounds, vinyl acetate;and copolym'ers of-{ vinylchloride r a u r minutl; .ahaeanielongafion with viny1icen'e-chl r q j ,Th fiet Wmrl 65- 1 of is zjnncerastre e ofL1 ;000"pounds per square 1161' of th q u c i iq fi Q- S'? plastlclm e inch. :A'film;0;004inchth ickjmadefrom thecom h ev il r WWP ?P Ti p itionw s"una t "arterimmer i ein water 9 riw' l j Pii W 9fi J Li etizs -"c. for losers; d tie t 4'.2i%-;b fjits 5i z 9 i weight during irnmersion -i 1i a1 25: c; rer=the ofjheietraethyl, tetrabutyl-and tetrahexyl-esd In t 0 47 f ters of thicdisuccinid acidwith Zpartsof awelF samepem 9 z; 1,3 e upon xe known light stabilizer, dibutyl tin dilaurategi-and P for Sm r tG f hlsp lclzer .65 parts of a viny i gfi aceate 1S non-toxic, and has' a. plast1c1z1ngeffic1ency polymer resin containing around 96%; of the 1 u ll g 1 23. 9? q. 9 ;1?. I '1 chloride in tiiefbelymer, using esm n two-roll 55 PP i 1i a d tision r application, mill;fclear flexilo eshee'ts wer cbtained which s r NQ 4,95 2, filed Januar V shQWed no evidence'of fitveati g out of the 5 T i v t cnr' is sceptiblc 01"".

' ;W-ithinthescope'oithcetppendedclaim iilc aimi .T.::*.,@1.. molde'd s'pecim en H 'f tl' c'' afilj ai '25 Amla-stic-compositioncomprisingra resinous vinyl resin and if riousltcti'a y g h i m f t r l z'sel tedq from;.;the classwconsistingof nates" er; the invention: i The compa b l y '.0 the polymers cf at leastone jmonomericzvinyl the resin with the'plasticizer was '100%in each compound-including a vinyl halidecfand contains case.v a 1 'ing. at least 85%;:01 thehalide in the rfpolymer, fl flfi' v U v a JPLAdTIGIiZEli EVALUATION;

I; g a V -[Cl1aracteristics of mglded resin sp qi e vl 1 5 g e I e a V v 851? V xrac 1011 V pnga- Name :51. T1= o. v $33K '19? Percent Oilat Water ""P-ii' foent J 0. mach Tetraethyl,thiodisuccinate,;; 38.0. V l7.4 v 12.0 12.9 750 I 2, 790 335 Tettaisopropyl thjodisuccina 40.8 -l3.5 8.6 2.0 525 I 2,530 7 330' Tetrabutylthiodisuccinatenen 38.0 -27.3'- 17.0 0. 34 57 2, 52o. 332 Tetra} (2-,ethylbutyl)" thiodt, h V succinate 40.5 7-2515. 15.6 0-5 740'- 2,425 -350 Tetrahexyl thi0disuccinate- 7 38:8 -32. 23.0 0.40 700. 2,350 330 'The'tetramethylester of-thio'disuccinic'acid is andicellulos'e este'rsof' thosefattyaci'cls having compatible Witlrthe' vinyl resin, .but sweat-out two to' four carbon' atoms, said-composition condifliculties arise. The tetra(2 -ethylhexyl) ester 'taining a plasticizer for thejfre'sinous material of thiodisuccinic acid is compatible withtheresin comprising an esterselected from the class conin 33% plasticizer concentration, but this i's near sisting of .the tetraalkyl and. tetrabenzyl esters of theborderline of compatibility therewith; The the saturatedthio-bis-dicarboxylic acids and the tetrabutyl thiodisuccinateappears .to beafn ost. hexaalkyl esters '-of ,,theqsaturated" thio-bijsjtrivaluable plasticizer'ofthisseries of compounds fqr carboxylic a'cids, each of. the allsyl groupshaving use with the polyvinyl chloride "resins and the from one to ten' ca'rbon atomaan'd said carboxylic vinyl chloride vinyl acetatecopol'ymer resins; acids-having at least eight carbon atomsandcon This particular compound possesses properties taining only carbon, hydrogen oxygen and sulfur; very similar to dioctyl phthalate in most respects 2:, A plastic composition comprisinga resinous afiecting itsplasticizing efficiency for the resins, material selectedfrom thecla'ssconsisting of the while being superior to the latter in evaporation polymers of at least one monomericjvinyl com rate, heat stability, and milling life; The hexapound including a vinyl'halide and containing at ethyland hexabutyl esters of thioditricarballylic least 85% of the halide in the polymer, and cellulose esters of those fatty acids having two to I a a} four carbon atoms,said composition'containing a of the. resinouscomposition. The lower tetra- I alkyl and tetraalkoxyalkyl thiodisuccinates such yl)thiodisuccinates are compatible with cellulose I acetate; and impart to the latter propertiesgem erally similar to those impartedjtheretojby di" ethyl phthalate,-which .isa widely. used. commercial plasticizer for cellulose acetate. j The. fdllowing lillustrates the plasticizing ei'liciency of 'tetrabutyl 1 thiddisuccinate f;orf vinyl plasticizer for the resinous material comprising a polymer of at least one monomeric vinyl compound including a. vinyl halide and containing at "A plastic'compos ition containing camera Vinyl.

1 resin; "1'%"of le'adstear'at'eg" 2% oflith'ar'ge, and

least of the halide in the polymer, said composition containing a plasticizer' for said polymer,

comprising anester' selecte'd from the class C011. sistingof the tetraalkyl and tetrabenzyl esters 'of saturated thio-bisedicarboxylic acids and the hexaalkyl. esters of. thio-bis-tricarboxylic acids,

each of'the alkyl groups having from one to ten carbon atoms, and said 'carboxylic acids having at least eight carbon atoms and containing only carbon, hydrogen, oxygen and sulfur.

4. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polymer comprising a tetraalkyl ester of a thio-bis-dicarboxylic acid wherein each alkyl group has from two to ten carbon atoms and. said thiodicarboxylic acid has at least eight carbon atoms and contains only carbon, hydrogen, oxygen and sulfur.

5. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polymer comprisinga tetraalkyl ester of thiodisuccinic acid.

6. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polymer comprising tetrabutyl thiodisuccinate.

'7. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polymer comprising tetrahexyl thiodisuccinate.

8. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polymer comprising tetraisopropyl thiodisuccinate.

9. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polymer comprising tetra(2-ethylbutyl) thiodisuccinate.

10. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polymer comprising tetrabenzyl thiodisuccinate.

11. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and contain-. ing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polytmer comprising hexabutyl thio-bis-tricarbalyla e.

12. A plastic composition comprising a resinous polymer of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, said composition containing a plasticizer for said polymer comprising hexaethyl thio-bis-tricarballylate.

13. Process for plasticizing and softening a resinous material selected from the class con-- sisting of the polymers of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, and cellulose esters of those fatty acids having two to four carbon atoms, which process comprises admixing with such a resinous material an ester selected from the class consisting of the tetraalkyl and tetrabenzyl esters of the saturated thio-bis-dicarboxylic acids, hexaalkyl esters of the saturated thio-bis-tricarboxylic acids, each of the alkyl groups having from one to ten carbon atoms, and said carboxylic acids having at least eight carbon atoms and containing only carbon, hydrogen, oxygen and sulfur.

' 14. Process for plasticizing and softening a resinous material selected from the class consisting of the polymers of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, and cellulose esters of those fatty acids having two to four carbon atoms, which process comprises admixing with such a resinous material a tetraalkyl ester of thiodisuccinic acid.

15. Process for plasticizing and softening a resinous material selected from the classconsisting of the polymers of at least one monomeric vinyl compound including a vinyl halide and containing at least 85% of the halide in the polymer, and cellulose esters of those fatty acids havingv two to four carbon atoms, which process '1 wherein the resinous material is a copolyme comprises admixing with such a resinous material tetrabutyl thiodisuccinate.

16. Process for plasticizing and softening a resinous material selected from the class consisting of the polymers of at least one monomeric vinyl compound including a vinyl halide and containing at least of the halide in the polymer, and cellulose esters of those fatty acids having two to four carbon atoms, which process comprises admixing with such a resinous material a hexaalkyl ester of thio-bis-tricarballylic acid.

17. A plastic composition as defined in claim 1 wherein the resinous material is polyvinyl chloride.

1 8. A plastic composition as defined in claim of vinyl chloride and vinyl acetate.

19.'A plastic composition as defined in claim 1 wherein the resinous material is a copolymer of vinyl chloride and vinylidene chloride.

LAWRENCE W. NEWTON.

REFERENCES CITED Ehe following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. A PLASTIC COMPOSITION COMPRISING A RESINOUS MATERIAL SELECTED FROM THE CLASS CONSISTING OF THE POLYMERS OF AT LEAST ONE MONOMERIC VINYL COMPOUND INCLUDING A VINYL HALIDE AND CONTAINING AT LEAST 85% OF THE HALIDE IN THE POLYMER, AND CELLULOSE ESTERS OF THOSE FATTY ACIDS HAVING TWO TO FOUR CARBON ATOMS, SAID COMPOSITION CONTAINING A PLASTICIZER FOR THE RESINOUS MATERIAL COMPRISING AN ESTER SELECTED FROM THE CLASS CONSISTING OF THE TETRAALKYL AND TETRABENZYL ESTER OF THE SATURATED THIO-BIS-DICARBOXYLIC ACIDS AND THE HEXAALKYL ESTERS OF THE SATURATED THIO-BIS-TRICARBOXYLIC ACIDS, EACH OF THE ALKYL GROUP HAVING FROM ONE TO TEN CARBON ATOMS, AND SAID CARBOXYLIC ACIDS HAVING AT LEAST EIGHT CARBON ATOMS AND CONTAINING ONLY CARBON, HYDROGEN, OXYGEN AND SULFUR. 